Spectactors watch as a Soyuz MS-02 rocket launches American astronaut Shane Kimbrough of NASA and Russian cosmonauts Sergey Ryzhikov and Andrey Borisenko, both of Roscosmos, into orbit from Baikonur Cosmodrome, Kazakhstan on Oct. 19, 2016. The trio is beginning a four-month mission to the International Space Station.

A Russian Soyuz rocket launched an American astronaut and two Russian cosmonauts into orbit this morning, beginning a two-day journey to the International Space Station.

At 4:05 a.m. EDT (0805 GMT) today (Oct. 19), the trio lifted off from the Baikonur Cosmodrome in Kazakhstan, riding on a Russian Soyuz MS-02 spacecraft — the second upgraded Soyuz spacecraft to carry new crewmembers to the space station (the first launched in July).

Roscosmos cosmonaut Andrey Borisenko (top) of Russia, NASA astronaut Shane Kimbrough (middle) and cosmonaut Sergey Ryzhikov climb the ladder to the elevator as they prepare to board the Soyuz MS-02 rocket for launch, Wednesday, Oct. 19, 2016 at the Baikonur Cosmodrome in Kazakhstan.

(Image credit: NASA/Joel Kowsky)

After launching, the crew will change out of their launch suits into more comfortable clothing for two days of tests on the upgraded Soyuz spacecraft, Kimbrough said in a news conference in July. (They'll change back into their suits when they arrive.) The craft will orbit Earth 34 times as it catches up with the space station, finally making contact and docking on Friday, Oct. 21 at 5:59 a.m. EDT (0959 GMT). The hatches between the spacecraft and station will open at around 8:35 a.m. EDT (1235 GMT) and the crew will be greeted by the current three-person crew. That whole process will be webcast live on Space.com, courtesy of NASA TV.

This mission is Kimbrough's second; he first flew on the space shuttle on a space station construction mission in 2008. While in orbit, the astronauts expanded the space station to enable it to house six crewmembers rather than three.

Borisenko will be making his second visit to the International Space Station as well. He commanded the station during 2011's Expedition 28; before that, he worked in Mission Control for the Russian space agency, Roscosmos, for years and acted as a flight director for the space station Mir as well as the International Space Station.

This launch is Ryzhikov's first spaceflight, although he is an experienced air force pilot. Microgravity will be a new experience for him, the crew revealed during the news conference.

NASA astronaut Shane Kimbrough and Russian cosmonauts Sergey Ryzhikov and Andrey Borisenko posed in front of the Soyuz MS-02 spacecraft on Oct. 13, 2016, less than a week before their Oct. 19 launch to the International Space Station on that spacecraft.

(Image credit: NASA/Victor Zelentsov)

"It will be neat watching Sergey, for the first time, learning how to fly, and Andrey and I could be laughing at him," Kimbrough joked. "Nah, it will take us a few days to get back into flying mode as well," he added.

The new arrivals will join NASA astronaut Kate Rubins, Japanese astronaut Takuya Onishi and Russian cosmonaut Anatoly Ivanishin, who have been alone on the station since Sept. 6. Their stay has been longer than expected: This mission was originally scheduled to launch Sept. 23, and the other three crewmembers would have returned in October; the Soyuz launch was delayed for technical reasons just a few days before the original date.

While there, the crew will welcome aboard supply spacecraft, including a Japanese H-II Transfer Vehicle that was originally scheduled for Sept. 30, and will continue the station's ongoing research into how physics, chemistry, biology and human physiology function in microgravity. (Several experiments for the station's U.S. segment launched on Orbital ATK's Antares rocket last week.) The cosmonauts have their own set of experiments, as well.

"The entire spaceflight is like one big experiment; not just ours, but everyone's," Ryzhikov said at the news conference, using a translator. "[It] has many parts: For example, we are testing new technology, there is a scientific component, we'll do experiments on the mice that will fly along with us, and the crew itself is kind of like a lab rat."